Rotating loudspeaker



Nov. 19, 1957 E. MIZRAHI ET AL ROTATING LOUDSPEIAKER Filed July 26, 1955 INVENTOR. 671' Ma'z/w'wz' Q4/2 9? P070 g V. J t United States Patent ice PM ifif'flifi 1 2 adapted to bear on and mesh with bevel gear 33 secured to motor 34.

2,813,928 ROTATING LOUDSPEAKER Eli Mizrahi and Andrew Pino, Brooklyn, N. Y. Application July 26, 1955, Serial No. 524,377 4 Claims. (Cl. 179-1) This invention relates to a rotating loudspeaker and more particularly to rotating electrically actuated loudspeaker.

It is an object of this invention to provide a loudspeaker mounted on a rotatable shaft.

It is another object to provide a loudspeaker disposed in balanced relationship on a rotatable shaft.

It is a further objective to provide a loudspeaker adapted to disseminate acoustical vibrations about a rotating axis.

It is a further objective to provide a loudspeaker with a baflle plate secured to the speaker month.

These and other objectives of this invention will become apparent upon reading the following descriptive disclosure taken in conjunction with the drawing in which;

Fig. l is a perspective view of the loudspeaker showing the manner of mounting the rotatable shaft to the loudspeaker mouth,

Fig. 2 is a front view showing a baffle plate secured optionally to the rim of the loudspeaker,

Fig. 3 is a detail section view showing the manner of insulating the rotatable shaft from the rotating electrical contact sleeve, and

Fig. 4 is a detailed section view broken away to show the manner of securing the counter-weight arm to the speaker rim.

Turning to the drawing a conventional loudspeaker is provided with a conventional grille 11 having a rim 12. The speaker 10 is provided with a conventional insulating plate of plastic 13 secured to the grille 11 by a rivet 14. The plate 13 is provided with electrical terminals 15 and 16 respectively. Terminal 15 is contacted (not shown) electrically to a conventional voice coil 17 and then is grounded to rivet 14 by wire 18 to the grille 11.

An important feature of this invention is the securing of the rotatable element to loudspeaker.

The loudspeaker rim 12 of the grille 11 is secured to a top rod 19 having a cut-back lip 20 by means of a rivet 21. The rod 19 is provided with a journal rod 22 of lesser diameter than rod 19.

A stabilizer bearing block 23 is provided with an aperture to receive the journal rod 22 and with a pair of spaced-apart apertures adapted to receive bolts 24. Bolts 24 may be secured into the ceiling or other rigid structure of a building room or the like.

The bottom of the grille 11 is secured to a bottom rod 25 having a cut-back lip 26 by means of a rivet 27.

The bottom rod 25 is provided with an insulator tubular sleeve 28 of electrically insulating material (Fig. 3).

The sleeve 28 is securely fixed to rod 25 by means of one or more set-screws 29. A tubular flanged top slip collar 30 is securedly disposed over the insulator sleeve 28 and secured thereto by one or more set-screws 31. Thus ring 30 is fully insulated electrically from rotating rod 25 yet it rotates therewith.

The bottom rod 25 is provided with a bevel gear 32 A slip clamp, preferably bifurcated and consisting of two clamp arms 35 has each of the arms 35 provided with a curvatured palm 36 adapted to closely contact flanged slip collar 30 thereby effecting good electrical contact.

As shown in Figs. 1 and 2 the arms 35 behave in opposition to one another thereby holding the rod 25 steadily. Also the clamps 35 may help support the weight of the loudspeaker where the flange of the collar 30 rests upon the palm sections 36 of arms 35.

In the embodiment shown the arms 35 are secured to opposing ends of a square suitably apertured insulator block 37 by means of metal bolt fasteners 38 which effect electrical contact between both arms 35.

The insulator block 37 is also provided with a centrally disposed aperture adapted to securingly receive bolt and nut 40. The bolt 40 is secured to a part of the rigid support frame 41 which may be suspended by conventional means from the ceiling of the auditorium in which the loudspeaker is located.

Other means of effecting a slip or running contact between collar 30 and an electrical arm 35 is to employ but one arm preferably having an aperture therein for receiving said collar 30.

In the operation of this rotating loudspeaker, while good acoustical results were obtained, it was found that the loudspeaker was unbalanced and therefore set up deleterious vibrations. To overcome the deleterious vibrations a counter-weight 42 was secured to a metal strap 43 having an apertured end flange 44 (Fig. 4). The flange 44 may be secured directly to the grille rim 12 (Fig. 4) by means of threaded screw 45 and good balance is thereby obtained through all rotational cycles.

Preferably the speaker is operated at about 40 to 60 revolutions per minute. Higher speeds are disadvantageous to the production of pleasing acoustics. At the speeds employed preferably but optionally a baffle 46 is employed to eliminate dead sound pockets.

The baflle 46 may be made of many materials but wooden or plastic circular baffle having a vertically disposed slot 47 is preferred. The baflle 46 is secured directly to the mouth or rim 12 of the speaker by means of a plurality of screws 48. Also the baffle is provided with a plurality of apertures 49 disposed on each side of slot 47 for the obtaining of heat acoustical results.

As shown in Fig. l, the terminal 16 is secured electrically by wire 16X to collar 30 and secured thereto by soldering. A wire (not shown) leads to voice coil 17. Thus the electrical impulses pass from a conventional amplifier unit 50 into the arms 35, thence to collar 30 and wire 16X to terminal 16 whence the impulses are led to voice coil 17. The ground or return wire from coil 17 leads to terminal 15 whence final grounding is effected through wire 18 to grille 11 and rod 19.

The invention has been described broadly and by illustrative embodiments but it is not to be limited to the described embodiments.

We claim:

1. A rotatable loudspeaker for attachment to overhead structure and for disseminating sound to an audience below comprising a metal grille, a voice coil secured fixedly to said grille, a top vertical shaft secured at its bottom end fixedly to the top of said grille and having an axle at the other end, a bottom shaft secured at its top fixedly to the bottom of the grille, a removeable insulator sleeve secured to said bottom shaft, a metal slip collar removably secured to said insulator sleeve and insulated from said bottom shaft, means for rotating said bottom shaft and secured thereto, a bearing block having an aperture therein for receiving said axle of said top shaft and 3" adapted for securing to a ceiling support, a metal slip clamp disposed against said metal collar in sliding contact thereto, a bottom support structure for holding said loudspeaker, means for securing said metal slip clamp in insulated relationship to said loudspeaker support, electrical conduit means for securing said slip clamp to an amplifier unit, electrical conduit means for fixedly securing said collar to said voice coil, and electrical conduit means for electrically securing said voice coil to said grille, whereby electrical sound impulses travel from said amplifier to said slip clamp and thence to said collar and then to said voice coil, said voice .coil having a return conduit to the grille, which grille is grounded through the top shaft and bearing block to said ceiling.

2. The apparatus of claim 1 wherein the slip clamp comprises a pair of clamp arms disposed in sliding contact opposed relationship to said collar, bolt means for electrically and mechanically securing said arms in spaced relationship, an insulator block having a central aperture 2 and lateral apertures, said bolt means belng disposed through said lateral apertures and a rod disposed through said central aperture in insulated relationship to said bolt means for securing said insulator block to said loudspeaker support.

3. The apparatus of claim 2 having a non-metallic bafile secured to said grille, said bafile having a vertically disposed slot and further having a plurality of circular apertures disposed on each side of said vertical slot whereby dead sound pockets are eliminated during the rotation of said loudspeaker grille and the voice coil therein.

4. The apparatus of claim 3 comprising a weight bracket arm secured to the base of the grille and extending away from the voice coil, and a counterweight secured to the extending end of said weight bracket whereby the weight of the grille and voice coil extending beyond the plane of the grille face is compensated thereby eliminating undesireable vibrations in the grille.

References Cited in the file of this patent UNITED STATES PATENTS 2,434,469 Myers Jan. 13, 1948 2,491,674 Markowitz Dec. 20, 1949 2,622,692 Leslie Dec. 23, 1952 

